Electric erasing machine



July 12, 1938. J. MISURACA ELECTRIC ERASING MACHINE Filed Feb. 24, 1936 INVENTOR a/"aca 9 fl% ATTORNEY.

Zea/s 7/Ls Patented July 12, 1938 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to an electrically operable erasing device of a simple, durable character and constructed in such a manner that the complete device, including the motor which drives the erasing element, may readily be made sufliciently small to be carried in the pocket of the user.

More specifically stated, the invention pertains to the combination, with a novel, compact, electric motor, of a hollow rotatable shaft extending through said motor and rotatable thereby while said motor is held in the hand of the operator; and the further combination with said shaft, of an elongated eraser element extendible through said shaft and having an applicator portion to project from an end portion of said shaft.

An object of the invention is to overcome disadvantages of machines using short sections of erasers which tend to jump out while the machine is in operation, thereby injuring the drawing surface.

Another object of the invention is to reduce the loss of time in replacing short eraser elements frequently, and also to effect economies in the usable portions of said eraser elements inasmuch as erasers cannot be securely held in a chuck when below a certain minimum length. Short erasers are therefore each only about fifty percent usable.

Other objects, advantages and features of the invention will hereinafter appear.

Referring to the accompanying drawing, which illustrates what is at present deemed to be a preferred embodiment of the invention,

Fig. 1 is a view of the complete device showing the same partly in side elevation and partly in vertical mid-section on line ll of Fig. 2.

Fig. 2 is an end elevation thereof, a portion of the handle being broken away to contract the view.

Referring in detail to the drawing, the motor casing comprises a central sleeve portion 5 and end portions 6 and 1, said end portions being securely fitted within the end portions of said sleeve. Around the central portion of said sleeve is removably secured a band 8 having at one side an internally threaded boss 9 into which is secured a detachable handle l0, and a friction head H. The band 8 and handle l0 may be removed from the sleeve 5 by unscrewing the handle from the boss 9 to release the pressure exerted by the friction head it upon the said sleeve 5.

The rotatable armature I2 is secured to the sleeve shaft l3 which is supported by the ball bearings I4 and I5. Other main parts of the motor are the core l6, wire leads I! and I8 contained in the cord l8, brushes 20 cooperating with the commutator 2i, and a cooling fan 22.

As viewed in Fig. 1, the sleeve or tubular shaft l3 has a projecting portion at the left end of the motor casing. Mounted upon this projecting part of the shaft is a clutch-sleeve or chuck 25 having a tapered portion 26 with which cooperates a slip ring 21. This clutch is positioned to grip the projecting applicator portion of the elongated 10 abrading element 28 which, in practice, is fed through the sleeve from either end thereof. The 'chuck 25 is furnished with arms 28 to grip the abradlng element or eraser where it projects beyond the sleeve or tubular shaft l 3. 15

The eraser element may be circular, rectangular, or otherwise shaped in cross-section, as may be desired.

In using the device the operator may take hold of the attached handle ill, or, if desired, the handle need not be attached as the motor casing will ordinarily be made sufliciently small to be directly gripped by the hand of the operator.

A short eraser may be used by feeding it into the right end of the tube l3 as seenin Fig. 1, and using a small rod to push it into the clutch; or such an eraser may be inserted directly into the clutch.

Various changes of construction may be made by workmen skilled in the art, without departing from the scope of the claimed invention.

I claim:

1. In a device of the kind described, an electric motor comprising an armature, and a tubular open-ended shaft extending through said motor and rotatable thereby, the ends of said shaft being accessible at each end of said armature.

2. An erasing machine comprising a tubular shaft adapted to serve as a magazine for an elongated abrasive element and to have said element extensible from either end and a rotary chuck associated with said shaft and adapted to have the abrasive element longitudinally adjustably held therein for rotation therewith.

3. An erasing machine comprising a, motor 45 adapted to be held by the user of the machine and having an axial bore therethrough adapted to receive an elongated abrasive element and arotary chuck driven by said motor and arranged to serve as an applicator for the abrasive element 5 and to have said element longitudinally adjustably extensible therethrough from said bore.

4. An erasing machine comprising a motor having an axial bore therethrough adapted to serve as a magazine for an elongated abrasive element 56 masses abrasive element in position to be fed to said chuck.

d. An erasing machine comprising a'motor, a rotary chuck adapted to have extended therelliroligh and rotated therewithan elongated abrasive element, and a magazine for said abrasive element and-which establishes a driving conneetlon between said motor] and chuck, said magazine "being tubular and open at both ends v for introduction and extension of said element 30 relative thereto.

' more 5. BflSURACs. 

